Our Air Floor Covers are a lycra denim material on the top and red vinyl along the sides and bottom * They also feature our Smart-Mat Technology that includes Velcro along the edges to allow for connecting of units and non-skid material on the bottom * A 4 in wide white line down the middle makes it useful for practicing beam skills too * Purchasing a cover at the time of your Air Floor purchase also extends your warranty to two years * It is recommended to use Air Floor Covers with our non-Velcro Air Floor units